Quarter	Percent
1999-01-01	11.8
2000-01-01	15.5
2000-04-01	14.8
2000-07-01	13.8
2000-10-01	14.4
2001-01-01	17.3
2001-04-01	17.3
2001-07-01	16.6
2001-10-01	17.6
2002-01-01	20
2002-04-01	19.6
2002-07-01	18.9
2002-10-01	19.4
2003-01-01	20.6
2003-04-01	19.2
2003-07-01	18.6
2003-10-01	18.7
2004-01-01	20.5
2004-04-01	18.8
2004-07-01	17.7
2004-10-01	17
2005-01-01	18.2
2005-04-01	17.4
2005-07-01	16.2
2005-10-01	15.6
2006-01-01	15.8
2006-04-01	13.6
2006-07-01	12.1
2006-10-01	11.1
2007-01-01	10.8
2007-04-01	9.3
2007-07-01	8.5
2007-10-01	7.8
2008-01-01	7.6
2008-04-01	6.6
2008-07-01	5.7
2008-10-01	6.1
2009-01-01	7.8
2009-04-01	7.6
2009-07-01	7.7
2009-10-01	8.3
2010-01-01	10.7
2010-04-01	9.4
2010-07-01	8.8
2010-10-01	9.0
2011-01-01	10.1
2011-04-01	9.1
2011-07-01	8.4
2011-10-01	9.0
2012-01-01	10.3
2012-04-01	9.3
2012-07-01	9.1
2012-10-01	9.5
2013-01-01	10.9
2013-04-01	9.9
2013-07-01	9.1
2013-10-01	9.3
2014-01-01	10.4
2014-04-01	8.8
2014-07-01	7.6
2014-10-01	7.7
2015-01-01	8.6
2015-04-01	7.5
2015-07-01	6.8
2015-10-01	6.9
2016-01-01	7.1
2016-04-01	6.4
2016-07-01	5.8
2016-10-01	5.5
2017-01-01	5.5
2017-04-01	5.3
2017-07-01	4.6
2017-10-01	4.5
2018-01-01	4.1
2018-04-01	3.8